Actuator for circuit breaker alarm switch

ABSTRACT

A multipole molded case circuit breaker having a common contact operating mechanism for all poles is provided with an alarm switch to indicate when the operating mechanism has tripped. The alarm switch is mounted in a housing compartment adjacent to the compartment housing the operating mechanism. An insulating transfer actuator extends between these compartments and is operatively positioned to transfer motion of the operating mechanism releasable cradle for operation of the alarm switch, so that operation of the latter is related to fault current tripping of the breaker and not to opening thereof under normal operating conditions.

United States Patent [191 Gaskill [451 Apr. 23, 1974 1 ACTUATOR FOR CIRCUIT BREAKER ALARM SWITCH [75] Inventor: George Gaskill, Hatboro, Pa.

[73] Assignee: l-T-E Imperial Corporation, Spring House, Pa.

[22] Filed: Dec.ll, 1972 [21] Appl. No.: 313,683

52 us. or. ..200 308, 200/153 11,200/153 335/17, 337/79 511 1m. (:1. H01h 9/16 [58] Field of Search 200/153 T, 153 G, 153 H, 200/167 R; 335/17; 337/79, 376; 340/253 R [5 6] References Cited UNITED STATES PATENTS 3,171,927 3/1965 Klein et a1. 337/79 X 2,767,276 10/1956 Buchanan et a1. 00/153 T X 2,102,284 12/1937 Sandin 335/17 X 2,656,439 10/1953 Gelzheiser et al. 337/79 X Primary Examiner-Robert K. Schaefer Assistant ExaminerRobert A. Vanderhye Attorney, Agent, or FirmOstrolenk, Faber, Gerb &

Soffen [57] ABSTRACT A multipole molded case circuit breaker having a common contact operating mechanism for all poles is provided with an alarm switch to indicate when the operating mechanism has tripped. The alarm switch is mounted in a housing compartment adjacent to the compartment housing the operating mechanism. An insulating transfer actuator extends between these compartments and is operatively positioned to transfer motion of the operating mechanism releasable cradle for operation of the alarm switch, so that operation of the latter is related to fault current tripping of the breaker and not to opening thereof under normal operating conditions.

10 Claims, 7 Drawing Figures iATENTEI] APR 2 3 I974 SHEET 1 or 5 PATEMTEQAPR 2 3 1914 SHLET 2 [IF 5 Y -w WMN SHEEP 5 Eli 5 b EHN ACTUATOR FOR CIRCUIT BREAKER ALARM SWITCH This invention relates to multipole molded case circuit breakers and more particularly relates to novel means for mounting of an alarm switch therein.

In a typical multipole molded case circuit breaker, the insulating housing is divided into side-by-side compartments, each housing the contacts of a different pole. In this type of circuit breaker, space in each compartment is at a premium, and this is particularly so of the compartment housing a common operating mechanism for all poles of the circuit breaker. Because of this, auxiliary switches are usually mounted in the compartments that do not house the contact operating mechanism.

This proves to be a satisfactory arrangement for auxiliary switches since actuation thereof is related to main contact position, with the auxiliary switches usually being actuated by opening of the main contacts. However, the compactness of molded case circuit breakers presents great difficulties when an attempt is made to incorporate an alarm switch, since actuation of the latter is coordinated with the position of the cradle of the common operating mechanism for the main contacts, so that the alarm switch is actuated only when the cradle is in its tripped position.

In accordance with the instant invention, the alarm switch is mounted in-acompartment adjacent to the compartment containing the contact operating mechanism, and a transfer actuator extending between these compartments is provided to transmit motion of the cradle moving towards its TRIP position to actuate the alarm switch. As will hereinafter be seen, by positioning the alarm switch in a compartment that does not contain the contact operating mechanism, installation and adjustment of the alarm switch are facilitated. In addition, operating springs and other elements of the alarm switch and its operating mechanism are sized more freely and operation is more easily observed, thereby assuring correct assembly of the alarm switch with the circuit breaker mechanism.

Accordingly, a primary object of the instant invention is to provide a novel construction for mounting an alarm switch in a multipole molded case circuit breaker. I

Another object is to provide a construction of this type in which the alarm switch is mounted in a housing compartment that does not contain the contact operating mechanism, and a transfer actuator is provided to Sense movement of the operating mechanism cradle to its trip position and transmit this movement to operate the alarm switch.

Still another object is to provide a construction of this type in which the alarm switch is part of a novel sub-assembly, including relatively movable frame parts that are adjustable when the sub-assembly is mounted in the circuit breaker.

A further object is to provide a construction of this type in which the transfer actuator is provided with a biasing spring that also maintains the actuator seated on its pivot prior to mounting of the sub-assembly in' the circuit breaker.

These objects as well as other objects of this invention will become readily apparent after reading the following description of the accompanying drawings in which:

FIG. 1 is a plan view of a circuit breaker, including the alarm switch assembly of the instant invention, with portions of the circuit breaker housing cover being broken away to reveal operating elements.

FIG. 2 is a longitudinal cross-section of the circuit breaker of FIG. 1 showing the contact operating mechanism in its tripped open position.

FIG. 3 is asimplified side elevation of the contact operating mechanism in the trip position of FIG. 2.

FIG. 4 is a view similar to that of FIG. 3, with the contact operating mechanism reset and the circuit breaker closed.

FIG. 5 is a plan view of the alarm switch subassembly mounted in a circuit breaker.

FIG. 6'is a side elevation of the sub-assembly and selected elements of the circuit breaker, looking in the direction of arrows 66 of FIG. 5.

FIG. 7 is an exploded perspective of the alarm switch sub-assembly.

Now referring to the figures. Circuit breaker 10 of FIGS. 1 and 2 is a three-pole unit in which the poles l 1, l2, 13 are mounted in individual side-by-side compartments formed in base 14 of a molded insulating housing which also includes removable cover 15. In a manner well known to the art, each of the poles 11-13 is provided with an identical contact mechanism including main movable contact 16 operable into and out of engagement with main stationary contact 17. A single operating mechanism 18 disposed in the center compartment of housing l4, 15 is mechanically connected to the contact mechanisms of all poles 11-13 by transverse bar 19, so that common operating mechanism 18 is effective to cause simultaneous operation of the contacts in all three poles 11-13.

In accordance with the operation of automatic tripping means well known to the art (see US. Pat. No. 3,484,726 issued Dec. 16, 1969, to A. Strobel for a Trip Unit Latch Positioning Means for Constant Latch Bite), mechanism 18 automatically separates main contacts 16, 17 of all phases upon the occurrence of predetermined overload conditions. In this connection, operating mechanism 18 is provided with main operating springs 22 that bias contacts 16, 17 closed when operating mechanism cradle 23'is in its latched position of FIG. 4, being restrained therein by a latch system including secondary latch 24, primary latch 25 and common tripper bar 26. The latter is pivoted clockwise about its pivot 27 upon the occurrence of predetermined overload conditions, thereby releasing primary latch 25 which then releases secondary latch 24. In turn, the latter releases cradle 23 permitting it to pivot counterclockwise about its pivot 28 to the trip position of FIG. 3, wherein operating mechanism 18 is no longer effective to close main contacts l6, 17. In order to obtain an indication that circuit breaker 10 has tripped rather than merely having been opened through the operation of mechanism handle 29, circuit breaker 10 is provided with normally open alarm switch 30. The latter includes normally projecting operating member 31 which upon being depressed (moved into the housing of switch 30) brings about the closing of switch 30.

Switch 30 is part of sub-assembly 35 that is mounted by screws 31a, 32 in the outer housing compartment that contains the contact mechanism for pole 13. With particular reference to FIG. 7, sub-assembly 35 also includes adjustable frame member or arm 33 to which alarm switch 30 is secured by nuts and screws 36, 37. Screw 38 extends through clearance aperture 39 in leg 41 of stationary frame member 40 and is received by threaded aperture 42 in arm 33 to provide a pivotal support for member 33 with respect to frame member 40. Screw 43 extends through curved slot 44 in frame leg 41 and is received by threaded aperture 45 in arm 33, to clamp the latter in adjusted position relative to stationary frame member 40.

A pair of auxiliary switches constituted by microswitch units 51, 52 are mounted between arm 33 and stationary frame leg 53, being secured thereto by screws 54 that are received by threaded apertures in leg 53. Slab-like insulating transfer actuator 55 is pivotally mounted to pin 56 that extends from leg 41 toward the housing compartment containing operating mechanism 18 and is received in actuator recess 59. Post 57.extends upwardly from actuator 55 and is connected to one end of coiled tension spring 58. The other end of spring 58 is connected to pivot screw 38 by merely slipping an end loop portion of spring 58 on the threaded portion of screw 38 with the loading of spring 58 holding this end loop portion in a valley between thread convolutions. Thus, spring 58 biases actuator 55 in a clockwise direction with respect to FIG. 6 and, as seen in FIG. 5, also biases actuator 55 toward seating on pivot pin 56. As also seen in FIG. 5, actuator 55 is provided with recess 61 aligned with recess 59, with recess 61 receiving pivot pin 62 extending outboard from frame 63' of contact operating mechanism 18.

Actuator 55 is provided with an extension formed by pin 63 projecting through mechanism frame aperture 64. Pin 63 is positioned below the cutaway portion of screw head 65 that is positioned adjacent the outboard surface of releasable cradle 23 on the side thereof nearest pole unit 13. Thus, when cradle 23 is in its trip position of FIG. 3, screw head 65 is in a raised position so as to be spaced from extension pin 63. This permits biasing spring 58 to pivot actuator 55 so that sloped surface 67, at the end of actuator 55 remote from pivot recesses 59, 61, engages switch actuator 31 to depress the latter, thereby closing switch 30. In accordance with operation well known to the art, the closing of switch 30 is effective to energize an alarm circuit (not shown) which generates a signal indicating that circuit breaker has tripped open. With cradle 23 in its latched position of FIG. 4, screw head 65 is lowered, thereby engaging pin extension 63 and forcing actuator 55 to pivot counterclockwise with respect to FIG. 3, to a position wherein actuator surface 67 clears operating member 31 so that alarm switch returns to its normally open position wherein the alarm circuit (not shown) is deactivated. Auxiliary switches 51, 52 are provided with spring arm actuators 71, 72, respectively, that are engaged by the movable contact mechanism of pole 13 to operate microswitches 51, 52 from their normal positions upon the opening of main contacts 16 and 17 in accordance with operation well known to the art.

Even though the instant invention has been described in connection with a normally open alarm switch and a transfer actuator that actuates this switch when the cradle of the contact operating mechanism is in tripped position, it should now be apparent to those skilled in the art that with an appropriate alarm circuit the cradle operated alarm switch may be normally closed and/or the transfer actuator may actuate the alarm switch when the cradle is in its reset position.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now become apparent to 7 those skilled in the art. Therefore, this invention is to be limited not by the specific disclosure herein, but only by the appending claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

l. A circuit breaker including a plurality of pole units each having a set of separable cooperating contacts; a housing having a plurality of internal parallel compartments, one for each set of cooperating contacts; an operating mechanism in a first of said compartments operatively connected to operate the cooperating contacts in said first compartment and the cooperating contacts in a second compartment of said compartments adjacent said first compartment; said operating mechanism including a cradle, releasable latch means for maintaining said cradle in a reset position wherein said mechanism is operable to close the cooperating contacts in said first and second compartments, and biasing means for operating said cradle to a tripped position upon release of said latch means, with said cradle in said tripped position said mechanism being ineffective to close the cooperating contacts in said first and second compartments; a signalling switch disposed in said second compartment; said switch including an operating member movable between first and second po-' sitions wherein said switch is open and closed, respectively; a transfer actuator means extending into said first and second compartments in operative relationship with said member and said cradle whereby the position of said member is related to the position of said cradle and said switch is actuated to indicate release of said latch means; said switch also including a switch biasing means urging said member to one of said positions; an actuator biasing means urging said actuator means from a third to a fourth position; said actuator means when in said fourth position engaging said member and operating the latter to the other of its said positions; said cradle when in said tripped position operating said actuator means to said third position wherein said switch biasing means is effective to operate said member to its said one position; said switch and the transfer actuator means are elements of a subassembly also including a frame having a first relatively fixed por tion and a second relatively movable portion adjustably secured to said first portion; said switch being secured to said second portion and adjustably positionable with the latter; and a securing means accessible for positional adjustment of said second portion after said first portion is secured in said second compartment.

2. A circuit breaker as set forth in claim 1 in which the frame is disposed in said second compartment; said first portion including a pivot formation to which the actuator means is pivotally mounted.

3. A circuit breaker as set forth in claim 2 in which the actuator biasing means also biases said actuator means to seat on said pivot formation.

4. A circuit breaker as set forth in claim 3 in which the securing means pivotally mounts said first portion to said second portion; one end of said actuator biasing means being connected to said securing means.

5. A circuit breaker as set forth in claim 4 in which the securing means includes a clamping screw and a pivot forming screw, with said actuator biasing means being connected to the latter.

6. A circuit breaker as set forth in claim '5 in which the operating mechanism includes a mechanism frame having means providing a pivotal support for said actuator means.

7. A circuit breaker as set forth in claim 1 in which the subassembly also includes auxiliary switch means mounted to said first portion of said frame and operatively positioned for actuation by the cooperating contacts, in said second compartment, upon separation thereof.

8. A circuit breaker as set forth in claim 1 in which the subassembly consists of elements exclusive of said cradle and said releasable latch means.

9. A circuit breaker as set forth in claim 8 in which the frame is disposed in said second compartment; said first portion including a pivot formation to which the actuator means is pivotally mounted; said actuator biasing means also biasing said actuator means to seat on said pivot formation.

10. A circuit breaker as set forth in claim 9 in which the securing means pivotally mounts said first portion to said second portion; one end of said actuator biasing means being connected to said securing means. 

1. A circuit breaker including a plurality of pole units each having a set of separable cooperating contacts; a housing having a plurality of Internal parallel compartments, one for each set of cooperating contacts; an operating mechanism in a first of said compartments operatively connected to operate the cooperating contacts in said first compartment and the cooperating contacts in a second compartment of said compartments adjacent said first compartment; said operating mechanism including a cradle, releasable latch means for maintaining said cradle in a reset position wherein said mechanism is operable to close the cooperating contacts in said first and second compartments, and biasing means for operating said cradle to a tripped position upon release of said latch means, with said cradle in said tripped position said mechanism being ineffective to close the cooperating contacts in said first and second compartments; a signalling switch disposed in said second compartment; said switch including an operating member movable between first and second positions wherein said switch is open and closed, respectively; a transfer actuator means extending into said first and second compartments in operative relationship with said member and said cradle whereby the position of said member is related to the position of said cradle and said switch is actuated to indicate release of said latch means; said switch also including a switch biasing means urging said member to one of said positions; an actuator biasing means urging said actuator means from a third to a fourth position; said actuator means when in said fourth position engaging said member and operating the latter to the other of its said positions; said cradle when in said tripped position operating said actuator means to said third position wherein said switch biasing means is effective to operate said member to its said one position; said switch and the transfer actuator means are elements of a subassembly also including a frame having a first relatively fixed portion and a second relatively movable portion adjustably secured to said first portion; said switch being secured to said second portion and adjustably positionable with the latter; and a securing means accessible for positional adjustment of said second portion after said first portion is secured in said second compartment.
 2. A circuit breaker as set forth in claim 1 in which the frame is disposed in said second compartment; said first portion including a pivot formation to which the actuator means is pivotally mounted.
 3. A circuit breaker as set forth in claim 2 in which the actuator biasing means also biases said actuator means to seat on said pivot formation.
 4. A circuit breaker as set forth in claim 3 in which the securing means pivotally mounts said first portion to said second portion; one end of said actuator biasing means being connected to said securing means.
 5. A circuit breaker as set forth in claim 4 in which the securing means includes a clamping screw and a pivot forming screw, with said actuator biasing means being connected to the latter.
 6. A circuit breaker as set forth in claim 5 in which the operating mechanism includes a mechanism frame having means providing a pivotal support for said actuator means.
 7. A circuit breaker as set forth in claim 1 in which the subassembly also includes auxiliary switch means mounted to said first portion of said frame and operatively positioned for actuation by the cooperating contacts, in said second compartment, upon separation thereof.
 8. A circuit breaker as set forth in claim 1 in which the subassembly consists of elements exclusive of said cradle and said releasable latch means.
 9. A circuit breaker as set forth in claim 8 in which the frame is disposed in said second compartment; said first portion including a pivot formation to which the actuator means is pivotally mounted; said actuator biasing means also biasing said actuator means to seat on said pivot formation.
 10. A circuit breaker as set forth in claim 9 in which the securing means pivotally mounts said first portion to said second portion; one end of said actuator Biasing means being connected to said securing means. 